严寒地区低收缩水泥混凝土道路修补砂浆的研究

以普通硅酸盐水泥、快硬硫铝酸盐水泥为胶凝材料制备水泥混凝土道路修补砂浆。针对修补砂浆收缩大的弊病,采用固体废弃物硼泥为原料制备微膨胀剂,并辅以消泡剂和PP纤维改善修补材料的收缩性能,同时兼顾修补砂浆的力学性能。试验结果表明:少量自制硼泥微膨胀剂的加入提高了砂浆密实度,从而提高砂浆的抗压强度和降低修补砂浆的收缩率;聚丙烯纤维和消泡剂同样对砂浆不同龄期的收缩率有改善作用。与普通修补砂浆相比,硼泥微膨胀剂、消泡剂和PP纤维降低了修补砂浆在高低温时的变形量,这有利于修补砂浆在严寒地区使用时与基体间的界面黏结耐久性。试验中所制备的修补砂浆抗压强度达到70MPa,抗折强度为16 MPa,收缩率为0.08%,优于《修补砂浆》(JC/T 2381-2016)标准中"普通刚性修补砂浆"的相关要求。

Research on Low Shrinkage Cement Concrete Road Repair Mortar in Severe Cold Area

Ordinary Portland cement and fast-hard sulphoaluminate cement are used as cementing materials to prepare cement-based road repairing mortar in this paper.Aiming at the disadvantage of large shrinkage of repairing mortar,solid waste boron slime is used to prepare micro-expansion agent,supplemented with defoamer and PP fiber to improve the shrinkage performance of repairing materials,while taking into account the mechanical properties of repairing mortar.The experimental results show that the addition of a small amount of homemade boron micro-expansion agent increases the compactness of the mortar,thereby increasing the compressive strength of the mortar and reducing the shrinkage of the repaired mortar;and polypropylene fibers and defoamers can also improve the shrinkage of the mortar at different ages.Compared with ordinary repair mortar,boron micro-expansion agent,defoamer and PP fiber reduce the deformation of the repair mortar at high and low temperatures,which is beneficial to the durability of the interface bonding between the repair mortar and the substrate.The compressive strength of the repaired mortar prepared in this experiment reaches 70 MPa,the flexural strength is 16 MPa,and the shrinkage is 0.08%,which are better than the relevant requirements of the"ordinary rigid repair mortar"in the standard of JC/T2381-2016"Repairing Mortar".